The hypothalamus is a complex region in the brain of humans, and even small nuclei within the hypothalamus are involved in many different functions. Cherry-sized and located below the thalamus, just above the brain stem. The hypothalamus is influenced by a complex interaction of hormones, the digestive tract, and the nervous system.

Hypothalamus holds a key in controlling weight. The hypothalamus is involved in controlling hunger and thirst. When a person’s stomach is empty, the blood sugar level decreases, and a message goes to the hypothalamus. If a person’s blood sugar is low, serotonin levels may also be low, and as a result of low blood sugar levels and low serotonin, the hypothalamus is stimulated and a person feels hunger. The hypothalamus play a role as the appetite center.

Stress, hormones, and depression also affect levels of chemicals in the body, such as serotonin, thus triggering the desire to eat. A change in hormones, for example, such as those associated with pregnancy, could increase appetite. Cortisol is a hormone that is secreted under stress. Women with higher levels of cortisol have been found in research experiments to snack on higher-fat foods than those with lower cortisol levels.